Fig. 8.

Immunogenicity assays of the PPV VLPs vaccine. a The titers of anti-PPV IgG in mouse sera immunized with PPV VLPs. Mice in each group (n = 5) were immunized with 20 µg or 40 µg of the PPV VLPs vaccine, and PBS as a control. b the HI antibody titers of mouse immunized with 20 µg PPV VLPs. Bars represented mean ± SEM (n = 5). c The stimulation indexes of mouse lymphocytes. At 56 dpi, spleen lymphocytes of the immunized mice and PBS group were isolated and then were stimulated in triplicate with conA. d The levels of cytokines secreted by the mice lymphocytes at 56 dpi. * P < 0.05; ** P < 0.01